OrbitStabilizer

OrbitStabilizer is a term used in orbital mechanics and control theory to describe a modular onboard system designed to keep a spacecraft in a desired orbit by actively counteracting perturbations. It combines state estimation, trajectory control, and propulsion command generation to minimize deviations in orbital elements such as semi-major axis, eccentricity, and inclination.

The system typically relies on a state estimator, often an extended or unscented Kalman filter, fusing measurements from GPS/GNSS, star trackers, altimeters, and ground or onboard reference signals. The control law translates estimated deviations into thrust or torque commands. Implementations may use chemical propulsion, electric propulsion, reaction wheels, or control moment gyroscopes, depending on spacecraft mass, propellant budget, and mission requirements.

Common control strategies include linear quadratic regulators, PID controllers, and model predictive control, sometimes with constraints to conserve propellant and respect safety limits. OrbitStabilizer can operate in a stand-alone mode or as part of a broader attitude and orbit control system.

Applications include satellite constellation maintenance, debris avoidance maneuvers, and station-keeping for GEO, LEO, or transfer orbits. It is especially relevant for small satellites with limited onboard resources, where efficient fuel use and robust estimation are critical.

Limitations include dependence on accurate models and sensors, fuel budget, actuator saturation, and communication delays. In practice, OrbitStabilizer must be designed to handle model mismatch, unforeseen perturbations, and component failures, often with fault-detection and recovery procedures.